1) One objective is to generate a library of monoclonal hybridoma antibodies reactive with the platelet membrane glycoproteins which bind to urate crystals. In order to achieve this, BALBc mice will be immunized either with whole platelets, platelet membranes, or purified membrane glycoproteins. Spleen cells from these mice will be fused with the X-63.657 line, single colony per well hybrids will be selected utilizing radioimmunoassay against whole platelet, platelet membranes, and the purified glycoproteins. Selected cultures will be expanded, and cloned, and the resulting clones rescreened on the purified membrane glycoproteins. Subsequently quantities of certain antibodies will be increased further by passage as ascites tumors. 2) We will study the interaction of plasma proteins with monosodium urate crystals to begin to investigate their modulation of crystal cell interaction by these proteins. To do this urate crystals will be incubated with plasma, the crystal bound separated from free proteins by centrifugation through sucrose, and the crystal associated peptides visualized and identified by two-dimensional O'Farrell gel electrophoresis. Specifically we will seek proteins that are specifically enriched on the crystal surface relative to plasma, and will also attempt to visualize cleavage events involving proteins of the complement and coagulation cascades. Ultimately these experiments will lead to studies of the ability of these plasma proteins to modulate crystal-cell interaction.